Re: Regression apparently caused by commit 088a40980efbc2c449b72f0f2c7ebd82f71d08e2 "ASoC: amd: acp: add pm ops support for acp pci driver"

[syed saba kareem]

On 11/3/23 04:41, Bagas Sanjaya wrote:
> On Thu, Aug 03, 2023 at 10:22:07PM +0300, Marian Postevca wrote:
> > I'm trying to develop a sound machine driver based on the acp legacy driver.
> > The first version of the driver was sent for review on the alsa mailing list this
> > spring: https://lore.kernel.org/all/20230320203519.20137-1-posteuca@xxxxxxxxx
> >
> > I'm trying to fix some of the issues that were brought up during the review back then,
> > but when I ported the patches to the latest commit on the for-next
> > branch, I noticed a regression where I couldn't hear any sound at all.
> >
> > So I started a bisect session and found that the first bad commit is:
> > ASoC: amd: acp: add pm ops support for acp pci driver
> > commit 088a40980efbc2c449b72f0f2c7ebd82f71d08e2
> > https://lore.kernel.org/lkml/20230622152406.3709231-11-Syed.SabaKareem@xxxxxxx
> >
> > If I revert this commit sound works as expected. So I started tinkering a little bit
> > with it and I believe that what happens is that the acp pci driver
> > enters the autosuspend state and never leaves this state at all.
> > I noticed this because if I increase the autosuspend delay to a much
> > larger value, then the sound works until that delay passes.
> > I added traces and I can see that when the delay expires the suspend callback snd_acp_suspend()
> > gets called, but the resume callback snd_acp_resume() never gets called.
> >
> > I'm no expert in runtime power management (though I did read a bit on it), so I don't understand
> > all the things that happen underneath, but one thing that is not clear to me is who's supposed
> > to mark activity on this device and keep it from entering autosuspend if the user wants to play
> > some sound? Shouldn't there be some counterpart that calls pm_runtime_mark_last_busy() ?
> > I looked through the code and can't find who's calling pm_runtime_mark_last_busy().
> >
> > Some help here would be welcome. Is there something missing in my machine driver code, or
> > is the runtime pm handling in acp pci driver wrong?
> Thanks for the regression report. I'm adding it to regzbot:
>
> #regzbot ^introduced: 088a40980efbc2
We were working on some other priority tasks, will upstream the changes

by next week.